Portable power hammer



Feb. 3, 1931. .1. A. STRAKEY ET AL 3 PORTABLE POWER HAMMER Filed March 18, 1930 2 Sheets-Sheet 1 Feb. 3, 1931. J. A. STRAKEY ET AL 1,791,332

PORTABLE POWER HAMMER ing the desired results. I II A still further object of the invention is to provide a C-sh'aped frame, one of the arms Patented Feb. 3, 1931 I I PATENT FECIE; ij

JQSEPH A. STRAKEY Ann AnRAM H. IBIITNER, or PHILADELPHIA, PENNSYLVANIA Y PORTABLE rowan HAMMER Application filed March 18, 1930. Serial No. 436,670.

Our invention relates to new and useful improvements in a portable power hammer and has for one of it-s'objects to provide an exceedingly simple 'and'effective device of this character, which maybe used as a tool for straightening and shaping metals and is particularly adapted for straightening and:

A further object of the inventionis to pro" vide a hammer of this kind havingunique structural details particularlyadapting it to the Work for which it 1s to be used and in which certain inherentcharacteristics of the parts are utilized to advantage in accomplish of which carries the'hammer elementwhile the other arm. supports an anvil, said C- shaped frame having a certain amount, of in 'herent resiliency which acts as a shock absorber. I I

'Anotherobject of the inventionis to utilize a coil spring connecting rod for transmitting motion from the revolving shaft to the reciprocating hammer.

Another object of the invention is to pro vide means forswingingly mounting the anvil on the frame whereby it'may be moved to one side for applying the hammer to articles or objects having deeply curved parts; I

'VVith theseends in View, this invention consists in the details of construction and combination of elements hereinafter setforth and'then'specifically designated by the claims. 7 In order tha'tthose skilled in the'a'rt'to which this invention appertains may under stand how tomake and use the same, we will 1 describe its construction in detail, referring by numerals to the accompanying drawings forming a part of this application, in which: Fig. 1, is aside elevation of a portable other arm 12,.generally called powerhammer constructed in accordance with our invention. 7 Fig. 2,is atop plan View thereofwith the dri'vepulley removed and a shaft broken away. w Fig. 3, isa section on the line 33 ofv Fig.1..

Fig. 4, isa similar section on theline l.4 of Fig. 1. Fig. 5, is an enlarged front" elevation of portion ofthe the'lhammer or tool carryingmember with the front plate removed.

Fig. 6, is an upper end view'thereof with the front plate-inplace andthe hammer shown on the guide attachedto the C-shaped frame. "Fig. 7, is. a fragmentarysectional view of the hammer'or-'tool carrying member, its guide and C-shaped frame and component parts thereof on approximately the line'7 .7 ofFig.5.

Fig. 8, a rear face view of the hammer. element removed from its guide and the connecting partsdetached. I i

.In carryingout our invention as herein embodied 10 represents the 'C-shaped frame,

one'ai'm 11 of which, generally called the lower arm, is preferably shaped similar to an I-section and this gradually blends into the the upper arm, through the curved portion. I a r Said upper arm is of the same general shapealthough of slightly greater thickness to provide a cylindrical portion 13Jhaving a bore ltfor the hammer shaft to be presently described. Projecting from the curved portion" of the frame in alignment with the arm 12is an extension forming acontinuation of the cylindrical portion 13 and also from said curved portion projects a boss 16 practically in endwise alignment with the arm llfor the reception of a trunnion or axlel? on which may be journalled a pulley 18 if the'latternis to be used.

The forward end of the arm 11' is fashioned to provide a plate 19; against which rests the base 20 of the anvil, said base being as indicated in Fig. 1, and said bolt is preferably located below the horizontal center of said base so that it may be swung to one side to permit entrance of work between the arms of the frame without interference by the anvil. The anvil base is normally held in an upright position by means of a latch or catch 22 slidably mounted in the base with its nose registering with a keeper aperture 23 in the plate 19 and said latch or catch is normally forced inward by a spring 24.

Projecting from the base 20 of the anvil is a post 25 having its upper portion threaded to receive a recessed collar 26, said recess adapted to register with the anvil proper 27 which is removably mounted upon the extreme upper end of'the post 25 and has a number of longitudinal slits in its lower end so that as the inclined walls surrounding the recess in the collar engage said anvil, the parts of said anvil between the slits will be drawn snugly against the post to prevent accidental displacement of the anvil.

The forward end of the upper arm 12 of the Q-shaped frame is also fashions d te provide a plate 28 to which is bolted the hammer guide 29. The hammer guide is provided with a dovetail guideway 30 longitudinally or vertically arranged fmthe re ception of the dovetail 31 which is formed on or carried by the rear face of the hainmer 32 and is slidably mounted in said guideway 30. Intermediate the ends or top and bottom of the hammer 32 is formed a through-and-t11rough opening 33 preferably of inverted pear-shape with a recess 34 in the rear face overlapping the lower end or apex of the opening 33 so as to be in communication with said opening 33. In the recess 34 is mounted a disc anchor 35 provided with a stem 36 projecting into the opening 33 to which is connected one end of the coil spring connecting rod 37 while the opposite end of said spring is attached to a ring 38 journalled on the crank pin 39 carried by the crank disc 40 housed in a suitable opening 41 in the guide 29 and fixed to the shaft 42 running through and journalled in the bore 14.

The revolving of the shaft 42 will carry the crank disc 40 with it and through the medium of the crank pin 39, will transmit motion; to the spring connecting rod 2? and through component parts for reciprocating the hammer or tool carrying member 32 and due to the circular formation of the anchor .disc 35, the upper end of the spring may follow the crank pin and therefore move transversely without materially fl xing the spring connecting rod.

On the front face of the hammer or tool holding member 32' may be removably mounted a plate 43 in order to cover the opening 33 and to some extent keep dust and other foreign matter from coming in contact with the spring and co-operating parts and if said front closure plate covers the entire front face of the hammer or tool holding member 32, then a hole 44 is formed therein which aligns with a hole 45 in the lower part of the hammer or tool holding member 32, said iole 45 being at right angles to and communicates with the tool shank receiving socket 46. W hen a tool such as shown at 47- in Fig. 1 is mounted in the socket 46 of the hammer or tool holding member 32, such tool will remain in place due to the friction between the tool shank and the walls of the tapered socket 46, but when it is desirable or necessary to remove the tool, an instrun'ie'nt can be placed in the hole 45 above the inner end of the tool shank and said instrument struck with sufiicient force'by a hammer or other object to force the tool from the socket 46 or at least sufficiently loosen the tool to permit its withdrawal by hand. 7

l Vhile the shaft 42 may be driven in any suitable manner, it is preferred that this be done by a belt (not shown) running over the pulley 18 and over a pulley 48 on the rear end of the shaft 42 which projects beyond the extension 15. Then if power is applied to the shaft 17 and should the hammer become jammed one or both of the pulleys 18 or 48 can slip and the prime mover will not be injured in any way. This is particularly advantageous where an electric motor is used and it is thought to be obvious that if preferred, the electric motor can be mounted directly upon the frame in place of the shaft 17 and pulley 18 in which-case a belt could run over a pulley on the motor shaft to the pulley 48.

In practice, the hammer is held in the hands of an operator and is slipped over the work to be operated on by raising the hammer or tool holding member 32 until a tool 47 is withdrawn from the anvil 27 or in some cases, the anvil is swung to one side by withdrawing the catch 22 from its keeper 23 to provide a greaterv space between the tool and the anvil structure. When the device is in a position to. begin operations, the power is turned on so as to revolve the shaft 42 and through the crank mechanism connected therewith will transmit motion through the medium of the spring connecting rod 37 to the hammer or tool holding member 32. It has. been found, because of the coil spring connecting rod 37, that the hammer or tool carried thereby has a tendency to strike a resilient blow and produce better work than where the ordinary hand hammer or where a power hammer having a solid connecting rod is used. Also,,due to the coil spring connecting rod, as soon as the blow is struck, the hammer is lightly moved away from the work and therefore tends to assist, the prime mover somevltl what like a fly wheel or at least relieve said prime mover of all the work necessary to retract the'hammer. It has also been found that a connecting rod made in this fashion tends to act as a buffer or shock absorber and the tool does. not vibrate to the same extent as when provided with a solid connecting rod. In addition to the resilient action of the spring connecting rod and its tendency to, absorb shocks incident to the striking of the tool on the work, the inherent resiliency of the C-shaped frame permits the arms-11 and 12 to spring back and forth away and toward from each other thereby absorbing any vibration which are not taken up by the spring connecting rod so that the user of the hammer is able to hold the same with great steadiness permitting application to any part of the work acted upon.

The compact arrangement of the structure makes it peculiarly adaptable for work on automobiles or other structures having intricate curves or complicated shapes which are often difficult to work upon with ordinary tools. I

Thetapered socket A6 enables the operator to readily and quickly place any desired tool in the machine and just as readily remove the Having thus'fully described our invention,

what we claim as new and useful is 1. A portable power hammer comprising a C-shaped frame, each arm of which has a plate formed at the outer free end thereof, a shaft journalled in one of said arms and extending through'and beyond the front face of the contiguous plate, a guide removably mounted on said plate and having an aperture through which the projecting end of the shaft passes and further having a dovetail 3. The structure set forth in claim 2 wherein the hammeris provided with a tapered socket at one end and a hole intersecting the opening in the guide, a hammer reciprocatnglymounted on said guide, said hammer having an inverted pear shapedchamberpassing all the way through said hammer from one faceto the'other and further provided with a recess in the rear face and incommunication with the lower end of the pear shaped chamber, one end of both the chamber and recess being closed by the face of the guide contiguous the rear face of the hammer, an

anchor rotatably mounted in the recess of the hammer, a crank pin projecting from the crank disc and extending into the pearshaped chamber, a coil spring connecting rod having oneend connected with the crank pin and the other end with the anchor so asto be located within the pear-shaped chamber and transmit motion. from the crank pinto said hammer and 'a plate removably mounted on the outer face of the hammer to, close the. pearshaped chamber. v

In testimony whereof, we have hereunto affixed our signatures. V JOSEPH A. STRAKEY, ABRAM I-I. BITNER.

guideway, a crank mounted on the'projecting i end of the shaft within the opening in the guide, a hammer, a dovetail on the rear face thereof for registration with the dovetail guideway to reciprocatingly mount the hammer on the guide, said hammer having a chamber therein and a coil spring connecting 7 rod Within. the hammer chamber and having one end attached to said hammerand the other end to the crank for transmitting motion from the crank to the hammer.

2. In a device of the kind described, a frame, a hammer reciprocatingly mounted on said frame and having a chamber, a shaft journalled in said frame, a crank carried by 

